Farmers often set fires illegally to clear land — a practice that has been made easier by the policies of Brazil's populist president, Jair Bolsonaro, who has consistently undermined the country's environmental agencies, and even accused NGOs of setting fires themselves.

The issue gained such momentum that French President Emmanuel Macron called it an "international crisis." "Our house is burning," he tweeted, saying the issue ought to be discussed during the upcoming G7 summit in Biarritz.

Bolsonaro, for his part, admitted that Brazil lacked the resources to control the fires, while insisting that foreign governments should not interfere with what he considers a Brazilian issue.